The present invention relates to electrodeposition and, more particularly, to an electrodeposition system and method that incorporate an anode having a backside capacitive element in order to minimize anode and/or plating solution degradation during non-plating periods (i.e., during idle periods before or after active plating).
Generally, electrodeposition (also referred to herein as electroplating) is a process in which plating material(s) and, particularly, one or more different metals are deposited onto a workpiece. Specifically, during electrodeposition, a plating solution (i.e., a plating bath) is contained within a plating container and plating material(s) is/are dissolved in the plating solution as stabilized metal species (i.e., as metal ions). A workpiece to be plated (i.e., an object to be plated, an article to be plated, etc.) and, particularly, a cathode and at least one anode are placed into the plating solution. The cathode and anode can be electrically connected to the negative and positive terminals, respectively, of a power supply in order to create an electric circuit. The power supply can subsequently be turned on so that electric current flows through the electric circuit from the anode to the cathode by means of ion transport through the plating solution. As a result of this current flow, electron transfer can occur at the cathode and anode such that the plating material(s) take up electrons at the cathode, thereby causing a layer of metal or a layer of a metal alloy (e.g., depending upon whether a single or multiple metal species are dissolved in the plating solution) to deposit thereon. The metal specie(s) in the plating solution can be replenished by the anode(s), if/when the anode(s) are soluble (i.e., if/when the anode(s) comprise soluble metal(s)) and the electric current causes the soluble metal(s) to dissolve in the plating solution). Additionally or alternatively, the metal specie(s) can be added directly to the plating solution.
Unfortunately, during non-plating periods (e.g., when the cathode is disconnected from the power source and removed from the plating solution and when the anode is exposed to the plating solution), any charged surface of the anode exposed to the plating solution can potentially cause unwanted reactions that result in anode degradation and/or plating solution degradation. Therefore, there is a need in the art for an electrodeposition system and method that minimize anode and/or plating solution degradation during such non-plating periods.